Welding

[busymate]

hello,
Can anyone tell me, if an aluminum frame has a crack in it can it be repaired?
Phil.

[DaveM]

Probably. But it depends where the crack is, how the frame is built, etc. The kind of work probably can't be down by the "welding shop down the street". It's pretty specialized work. And questionable if the work would be anywhere cheap enough to justify fixing instead of just buying another frame. But again, depends on what you're talking about.

[GeorgeET]

Its weldable by a experienced TIG welder.(Tungston Inert Gas)

Its thin metal so its got to be a very good welder. Find one and ask him.

[KC-Steve]

(07-23-2010, 10:44 PM)GeorgeET Wrote:  Its weldable by a experienced TIG welder.(Tungston Inert Gas)

Its thin metal so its got to be a very good welder. Find one and ask him.

Yeah, a qualified weldor would likely charge as much to fix it as it would cost to buy a new frame. But ya never know with the economy the way it is. I know a lot of weldors that are looking for jobs right now. The problem though, an unqualified weldor may cause more harm than good.

If you decide to go with a weldor to fix it, ask him what his certifications ("certs") are or has. Can he weld aluminum? And are his certs up-to-date?

In all honesty, most qualified, highly certified weldors would consider fixing a bike frame a "junk job" and prefer real money-making jobs.

Steve

[GeorgeET]

Do not know where you are or if its a MB or a RD bike. Nashbar (USA) has a big sale on frames as do some other dealers.

If the frame is cracked you got nothing to loose by trying to weld it. Try to cut a deal to pay if fixed.

I had some aluminum motorcycle cases welded once by finding a small shop doing commercial TIG aluminum welding of products and the welder welded it for me on his lunch break for a nominal fee. Be nice. Perhaps find a welding school in area and instructor can weld it as a demo.

Like I said depends on the bike and the frame quality to see if its worth a try. You keep most of the paint and original logos that way.

[cyclerUK]

Where on the frame is the crack?

[KC-Steve]

(07-24-2010, 02:58 PM)GeorgeET Wrote:  . . .If the frame is cracked you got nothing to loose by trying to weld it. Try to cut a deal to pay if fixed. . . .

Nothin' to lose except maybe your life in the wrong circumstances. Broken bone if lucky. An improper weld will break easier than the frame. A proper weld will be stronger than the frame.

Personally, I would avoid the guessing game and just get a new frame.

Steve

[GeorgeET]

10- 4 - Yes it has to be done properly, but that was said already. Out of context quotes not withstanding.

What I was thinking was that if the frame melts you will be no worse off than with a cracked frame. Qualified welder is a must and it is doable. As I said before.

Anyway till original poster gives more info I had enough of guessing.

[busymate]

Hello,
It was more of a general question really. I have seen a couple of really high end frames for sale cheap, with cracks in them. But was unsure weather repairable or not.
phil.

[KC-Steve]

(07-26-2010, 02:18 AM)busymate Wrote:  Hello,
It was more of a general question really. I have seen a couple of really high end frames for sale cheap, with cracks in them. But was unsure weather repairable or not.
phil.

Phil my answers above were "in general" and it would be good to note that people selling cracked frames probably realize the risk and cost of making a repair, otherwise they would make the repair themselves and sell them at a higher price.

Steve

[Bill]

To add to everyones good advice, here is my opinion. If I see a crack in a the frame the bike will never see the road again. Many uses for a retired bike frame after I put a hack saw through it to make sure it won't be rode again. Personally they are a danger to the rider and/or others around because if it went John Doe loses control hits someone then gets hurt as well as rider. Someone brings me a bike and I see it, I explicitly warning them of the dangers and offer them a bike with a discount for trade in. Then the frame gets to see Mr. Saw! Some bikes are just not worth the risk of fixing. Sorry all but I do have my own opinions about frames.

On a note to the people selling cracked frames, I really think they need to shut that little operation down.

[KC-Steve]

^^ Yeah and to make matters worse, Home Depot, Lowes, et. al. are selling cheapo welders to people who have no clue, and then they think they can fix anything. Those dept store welders might have "Lincoln" stamped on them but they are not professional machines. They are designed specifically for the mass markets. They cut corners on components so the price is lower than a professional machine. All I can say is, buyer beware. And BE AWARE.

Steve

[xerxes]

(07-26-2010, 08:44 AM)Bill Wrote:  To add to everyones good advice, here is my opinion. If I see a crack in a the frame the bike will never see the road again. Many uses for a retired bike frame after I put a hack saw through it to make sure it won't be rode again. Personally they are a danger to the rider and/or others around because if it went John Doe loses control hits someone then gets hurt as well as rider. Someone brings me a bike and I see it, I explicitly warning them of the dangers and offer them a bike with a discount for trade in. Then the frame gets to see Mr. Saw! Some bikes are just not worth the risk of fixing. Sorry all but I do have my own opinions about frames.

Cracked or damaged carbon and aluminum frames have probably had it, but steel frames, especially lugged ones, can be safely repaired. If a tube is damaged it can be swapped out and replaced with a new one and small dents can be filled with brass. However, the repair will only be economical on better quality frames made with lightweight tube sets. With cheaper, plain quage steel frames, the repair will likely cost more than the frame is worth.

[nfmisso]

(07-23-2010, 04:16 PM)busymate Wrote:  hello,
Can anyone tell me, if an aluminum frame has a crack in it can it be repaired?
Phil.

Don't do it.

Recently at work we have been looking for a shop that could weld some 6061 Aluminum structural frames. We have received butt welded test specimens from several shops, in an attempt to find a qualified welder. The test specimens have been sent to a certified testing lab to check for strength. All of the specimens have had brittle failure at the weld line. We're in San Jose CA, and have been trying different shops all over the Bay Area. Due to these issues, we have abandoned the welding design approach for our structural frames.

Brittle failure means that the weld fails with practically no warning. The metal outside the weld area has ductile failure, meaning that it bends and stretches before failure - a nice warning sign.

Given that my company could not find a welding shop in the SF Bay Area that could do a satisfactory job on aluminum, it is highly unlikely that you will find one either.

Bill has the right idea - I'd just use the metal cutting blade in my saws-all though - too lazy to hack saw the frame.

[Bill]

I'm only concerned for the safety of people, not to make a quick dollar or two. It is bad enough low end bikes are made cheap for the mass market industry. Yes I will say that they are tested and all that for imperfections, but when they break they break and are done.

[trevgbb]

(07-26-2010, 10:20 AM)xerxes Wrote:  but steel frames, especially lugged ones, can be safely repaired. If a tube is damaged it can be swapped out and replaced with a new one and small dents can be filled with brass. However, the repair will only be economical on better quality frames made with lightweight tube sets. With cheaper, plain quage steel frames, the repair will likely cost more than the frame is worth.

These frames are, of course, brazed and not welded, a different technique altogether. My local frame builder, making and repairing frames in Reynolds tubing, stopped production several years ago, in fact, I am not sure you can still get the tubing.

[KC-Steve]

(08-21-2010, 04:36 AM)trevgbb Wrote:  These frames are, of course, brazed and not welded, a different technique altogether. . . . .in fact, I am not sure you can still get the tubing.

Yes, brazing STEEL TUBING is a good option using a MAPP torch for frame building. I plan to try it someday since I have many years of soldering skills. However, it is expensive. You can find many tubing sources around the Internet.

http://www.cycle-frames.com/bicycle-frame-tubing/

Steve

[Darrenjs92ni]

Raleigh guarantee alloy frames for 5 years.

[xerxes]

(08-21-2010, 04:36 AM)trevgbb Wrote:  These frames are, of course, brazed and not welded, a different technique altogether. My local frame builder, making and repairing frames in Reynolds tubing, stopped production several years ago, in fact, I am not sure you can still get the tubing.

Reynolds has changed ownership a couple of times in the last couple of decades, but it is still going. In addition they have recently introduced a couple of new tube sets 853 and stainless 953 which can be left unpainted.

http://reynoldstechnology.biz/our_materials_953.php

Also, since the late 80's early 90's steel frames are more commonly TIG welded than brazed. Welding is cheaper, quicker and like fillet brazing allows more geometry variations than lugged frames where the frame butting angles are restricted by the availability of the lugs.

TIG welded, unpainted stainless 953 frame:


http://www.roadcyclinguk.com/bike-reviews/independent-fabrication-ssr-953/3315.html

[KC-Steve]

(10-25-2010, 09:44 AM)xerxes Wrote:  . . . Also, since the late 80's early 90's steel frames are more commonly TIG welded than brazed. Welding is cheaper, quicker and like fillet brazing allows more geometry variations than lugged frames where the frame butting angles are restricted by the availability of the lugs.

I would tend to disagree with welding being cheaper unless you are referring to materials ONLY. We have gone full circle now, back to my post#4.

Quote: . . . a qualified weldor would likely charge as much to fix it as it would cost to buy a new frame. But ya never know with the economy the way it is. I know a lot of weldors that are looking for jobs right now. The problem though, an unqualified weldor may cause more harm than good.

If you decide to go with a weldor to fix it, ask him what his certifications ("certs") are or has. Can he weld aluminum? And are his certs up-to-date?

In all honesty, most qualified, highly certified weldors would consider fixing a bike frame a "junk job" and prefer real money-making jobs.

Steve